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Simple Guide to Grow Light Spectrum: How To Get the Right Light Spectrum

It can be difficult to select the ideal grow light spectrum for your indoor plants. You may have heard of "color temperature" and be wondering what the appropriate range is for various plant growth stages. You may be looking for the best spectrum grow light for your indoor garden and wondering what the real spectrum is.

In this article, we will talk about some of the basics of the light spectrum and how the light spectrum affects plant growth for you to choose the best LED grow light for your indoor garden.

Grow Light Spectrum

Color Spectrum

A colour spectrum is a visual representation of all the colours present in light. Instead of using colour names to describe colours, scientists now use wavelength numbers as a much more precise method of measuring colour. The wavelength of a red might be 630 or 660. We see each of these as red, yet they are not the same colour.

The expansion of leaves as well as the growth of stems depends on red light, or wavelengths between 630 and 660 nm. Additionally, this wavelength controls seed germination, dormancy intervals, and flowering.

Since too much exposure to blue light (400–520 nm) may hinder the growth of some plant species, blue light needs to be carefully blended with light in other spectrums. Both the amount of chlorophyll in the plant and the thickness of the leaves are impacted by blue light.

To support the lower canopy's leaves, green light (500–600 nm) pierces through the top canopies' dense coverings.

The Far Red Light (720–740 nm) also penetrates dense upper canopies to promote the development of lower-canopy leaves. A plant requires less time to blossom when exposed to IR light. Far red light also has the advantage of encouraging plants to grow larger leaves than plants that are not exposed to this type of light.

Grow Light Spectrum

The range of wavelengths emitted by a light source is known as the light spectrum. When speaking of the light spectrum, the term "light" refers to the 380–740 nanometer visible range of the electromagnetic spectrum (nm). Radiation includes wavelengths in the infrared (700-106 nm), far-red (700-850 nm), and ultraviolet (100-400 nm) bands. The wavelengths that are important to plants are those that growers are most interested in. The visible spectrum (380-740 nm), which comprises PAR (400-700 nm) and far-red radiation, as well as UV radiation (260-380 nm), is detected by plants (700–850 nm). In terms of the light spectrum, indoor and greenhouse settings will differ in horticulture applications. In enclosed spaces, the whole light spectrum received by your plants will be covered by the spectrum of your grow light. In contrast, you must take into account that your plants in a greenhouse are receiving both grow lights and the sun's spectrum. The quantity of each waveband that the plant receives will have a big impact on growth in either case.

When referring to grow light spectrum, florescent bulbs are either warm white or cool white. That was helpful for fluorescent lights, but LED grow lights do not respond well to such designations. It is more accurate to discuss LED in terms of wavelengths and to show the true colour spectrum.

How the Color Spectrum Affects Plant Growth

Plants obviously need light to develop, but the quality of light is just as important as quantity. Plants can only use a limited range of light's spectrum for absorption. Plants utilise a spectrum of light called Photosynthetically Active Radiation (PAR), which has wavelengths ranging from 400 to 700 nm. Therefore, light that is produced outside of this range cannot be absorbed by plants and used for growth.

Additionally, differing light wavelengths might cause the plant to react in various ways. For instance, red light is useful for growing plants overall, but when used exclusively, it can lead to "stretched" plants that are tall with sparse leaves. Increasing the amount of blue light during the vegetative state can lead to more compact, stockier plants, which provides a more even canopy height and ensures that plants receive equal quantities of light. The plant's growth rate is then accelerated during the flowering stage by the addition of more red light, which "stretches" the plant and produces higher yields. This is due to the fact that in nature, a plant's response to the spectrum of light it receives signals specific climatic variables, such as the season.Because of this, it's crucial to have a "full-spectrum" grow light that contains a variety of light wavelengths.

Depending on the stage of development your plant is in, increasing the quantity of specific light colours can help your plant's growth. It is simple to understand why full-spectrum lights are the best for plant growth once you understand how different wavelengths are responsible for various plant reactions. Full-spectrum lighting employs a mixture of all hues at all phases of growth to most accurately resemble natural sunlight.

How to Get the Right Light Spectrum

Your grow goals will determine the best color spectrum. The optimal LED grow light varies depending on the stage of growth, as plants develop and move through their life cycle from seedling to adult, then flowering and fruiting. Thus, your chosen plant species will also influence the ideal color spectrum. Keep in mind that plants benefit most from light of all wavelengths in general, but they don't require equal amounts of each.

So what colour spectrum works best with LED lights? It ought to be somewhat similar to the spectrum that plants need. In general, green, yellow, and a lot of blue and red. It would be even better if you included some near IR and possibly even near UV. Remember to always check the light's output spectrum before purchasing a grow light for your indoor garden. The yields of crops grown under HPS grow lights can now be matched and even surpassed by modern LED grow lights that produce a white, full-spectrum light. To increase the productivity and quality of your grow, RayonLED has worked to improve the spectrum of our LED grow light fixtures.


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